Energy Innovation: Massive Solar Downdraft Tower Proposed in Arizona

The U.S.-Mexico border has been gaining attention lately, but not for what you might expect. Solar Energy, Inc. is attempting to build a massive hollow tower reaching 2,250 feet in height and 500 feet in width. If approved, this colossal structure would be able to generate 600 megawatt hours of electricity!

Solar Wind Energy is planning to build this structure, known as a downdraft tower, right on the border of Arizona and Mexico. This ambitious project will be in the shape of a large, hollow cylinder with an open top. With the help of a hot climate, heavy and humid air will be produced by spraying water into the opening. At approximately 50 miles per hour, this air will sink to the bottom and exit the tower through one of the 25 tunnels located at the base. Within these tunnels are turbines that will turn and generate electricity with the passing of the fast-moving air.

The Solar Wind Downdraft Tower

The company says “the Tower’s potential hourly yield would be 600 megawatt hours,” 100 of which will be used to provide energy to the tower. The remaining energy would then be sold to the power grid.

2018 marks the anticipated end date of this energy efficiency project. As stated on Solar Wind Energy’s website, “The Solar Wind Downdraft Tower has the capability of being operated with virtually no carbon footprint, fuel consumption, or waste production. The technology will generate clean, cost effective and efficient electrical power without the damaging effects caused by using fossil or nuclear fuels, and other known alternative power sources.”

David Ferris at Forbes.com reports in his article that the tower will also create thousands of jobs for the economy. In order to build the monumental tower, 2,500 construction and transportation employees and 1,000 manufacturing employees will be required. Following construction, about 750 permanent employees will be needed to maintain the tower and its 25 “generating plants.”

In an earlier version of the article, Ferris explains how negotiations are underway in order for Solar Wind Energy to obtain a lease from the Bureau of Land Management (BLM) for a 1,700-acre piece of flat, desert land adjacent to an Air Force bombing range. The tower must also receive permission from the city of San Luis, Arizona since the desired land is within city limits.

Although some see plans for similar projects and consider them far-fetched, Sharon Williams, director of development services for the city of San Luis, has other opinions regarding the tower. Ferris’ article quotes her saying, “With (Solar Wind Energy), they have already gotten permission and concurrence from federal agencies in Washington. They weren’t starting with the Air Force, they weren’t starting with BLM. They were starting at the top. It isn’t a guarantee of success, but it is a lot more feasible than a lot of the other things I’ve seen.”

Ferris found that it would also need an environmental impact report because of the following three threatened species that live in the vicinity of where the tower would be built: the desert tortoise, the flat-tail horned lizard, and the burrowing owl. Obtaining the necessary water may also become an issue as the company is planning to transport desalinated water from the Sea of Cortez, located over 45 miles away in Mexico.

President and CEO of Solar Wind Energy Ron Pickett spoke with Ferris and explained how it would require about $1 billion and an extra $100 million to acquire the water. A desalination plant will also need to be constructed, but this additional cost would be split between the original tower and another similar tower that the company is planning to build in Mexico. Regardless of the exact amount of water, Pickett claims that the tower will have the ability to recycle approximately 75 percent of what it uses.

Though the downdraft tower may take years to develop and millions of dollars to construct, the end result may prove to be extremely beneficial. As stated on the Solar Wind Energy website, “The Solar Wind Energy Downdraft Tower will provide clean renewable energy at a cost more favorable than nuclear plants with no negative impacts to our planet.”

” Due to lower capacities during winter days, the average daily output for sale to the grid for the entire year is approximately 435 megawatt hours”Lets take this at face value for daytime, but reduce it, assuming no power at night. Lets give it an 8 hour day. So now we are at say 150 MWH per day. Say 300 days per year: 45,000 MWH per year…or 45M KWH. If we charged $1 per KWH, absurdly expensive, it would still take around 30 years of operation to get our $1.2B back.Someone please help me…this seems more than a factor of 100 from being competitive. I think the author owes us an economic payoff calculation…otherwise there will be much misinterpretation–like mine–that may gave a fine project a bad reputation.

You are correct Bill, I said take the number at face value and then proceeded to discount it by a factor of 3, thinking that this tower would only work in the daytime when there would large temp differences between 2500 ft up and the desert floor. But even without my discount the numbers do not seem to work.So, I again invite the authors–of this article–and the Forbes author to help us with actual estimates of MWH per year according to the theoretical analysis by the company or the Israeli professor who originally proposed the project. In spite all the technical 2nd guessing in the comments, I actually trust that this professor understands the physics involved. I may be less sure that he would really be able to nail down actual construction, maintenance costs and costs of permits, environmental impact reports, etc on a very large project that seems to have little precedent to guide the estimates.I remember such a project being recommended in Israel more than a decade ago by this professor. If I remember correctly, it was rejected, not on economics, but rather because of objection by the Israeli Air Force because it would be a navigation obstacle near their Negev desert bases.It would be great fun if this project actually worked technically and economically. Despite the terrible visual impact, on paper it seems like it might provide significant power with a small footprint compared to solar panels or a wind farm of equal power. And it would seem to have fairly constant power during a large part of the day and perhaps a little into the evening, making this a much more valuable source than most windfarms.

On first reading, this struck me as highly impractical. The many incisive comments here made it clear why.Which leads to the question: Who/what exactly is meant by, “they have already gotten permission and concurrence from federal agencies in Washington”?What was the nature of the ‘permission’ and ‘concurrence’?Ferris’ follow-up report in Forbes if anything only serves to compound the uncertainty about the whole scheme. The CEO of the company evidently is relying on some unknown other company to put up the money and do the actual construction. The only prototype of the tower is a mere 4 feet tall (!). Nor is any mention made of the environmental and economic costs/hurdles of the pipeline presumably needed to deliver desalinated water to the Arizona site.Then there is the question of who will bear the costs of failure if the project were actually built. Suppose the constructed tower proves uneconomical to operate, and/or the company goes bankrupt. Can the tower be repurposed? Who would have to pay to demolish it? Consider this cautionary tale:http://www.abandonedonline.net/industry/marble-hill-nuclear-power-plant/Supposedly no government money is involved in the vneture. But does that include possible loan guarantees?In the current financial environment, it’s hard to imagine how a billion dollars or so of private capital would be available for such a high-risk, untested project.

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sudlin

April 29, 2014 21:32

Capacity figures are murky, permitting seems murky, number of employees to operate seems rediculous. Good points above, sea water and brackish water would corrode generators, how many times would you need to replace parts? Filtering of water for the vapor would be incredibly expensive. Would be nice to have some solid figures for this potential project.